A toner delivery mechanism is fundamentally disclosed by EP-B1 0 332 669. This is thereby a matter of a device for the pneumatic filling of toner from a bottle-shaped transport container into a toner reservoir in which toner is completely suctioned from the transport container with the assistance of underpressure and is thus conveyed into the toner reservoir. The toner reservoir is in communication with a developer station having only a single developer chamber. It contains a mixing means composed of a wire bow and a metering drum of cellular material arranged in the connecting region to the developer station via which toner, which is dosed in printing mode, is supplied to the developer station dependent on its filling level. The toner reservoir itself is divided via a filter into a suction space and a settling space, whereby the settling space is connected to the toner bottle via a hose and the suction space is coupled to an underpressure blower.
Further, WO 94/27193 discloses an electrographic printer means with which it is possible to print a band-shaped recording medium multi-color in simplex and duplex mode. To this end, the printer means contains a plurality of separate developer stations arranged successively or side-by-side that separately ink developer regions on an electrographic intermediate carrier (photoconductor) that are allocated to the developer stations.
In multi-color simplex mode, what is referred to as spot color mode, a print image is first transfer-printed onto the recording medium with a first color, the print image is then fixed, and the recording medium is then returned to the transfer printing station and a print image is printed with a second color and subsequently fixed in a second pass through the fixing station. The transfer printing station is thus traversed with a single recording medium in two recording medium webs arranged parallel next to one another. Corresponding developer regions on the photoconductor are allocated to the recording medium webs. Since photoconductors, whether bands or drums, cannot be arbitrarily wide, it is necessary to arrange the developer regions side-by-side on the photoconductor without significant spacing. The appertaining developer stations must thus also be arranged in close proximity next to one another. To this end, it has already been proposed to employ a single developer station with a plurality of separate developer chambers in which differently colored toner, for example red toner and black toner, is respectively contained.
When toner from a standard toner reservoir with a predetermined capacity is delivered to the developer chambers, then large-volume containers are needed for maintaining the printing operation. These require much space and can therefore not be employed in conjunction with a developer station having a plurality of developer chambers. When smaller containers are employed, this shortens the printing operation.
It has turned out that the great majority of printing is in only a single color, for example black, given multi-color printing with high-speed printers of said species. Only occasionally are individual areas of the print image emphasized with another color or are multi-color graphics or images inserted. Different degrees of consumption of the various types of toner thus occur. The printing time is thus limited by the capacity of the container having the toner that is used most. When, on the other hand, the containers are made of different sizes according to the statistical use, then there is the risk that, given a sudden, longer operation in multi-color, the differently colored toner components needed therefor will be prematurely used and the printing operation will therefore be interrupted.